Pressure and heat would directly or indirectly produce most of the casualties if a one-megaton bomb were detonated in the air over a typical U.S. city. 12 psi or greater (up to 2 1/2 miles): All but the most heavily reinforced concrete buildings are destroyed; 100% fatalities. 12 psi to 5 psi (2 1/2 to 4 1/2 miles): Frame and brick buildings are destroyed; combustible materials ignite spontaneously; 100% fatalities. 5 psi to 2 psi (4 1/2 to 9 miles): Some combustible materials ignite spontaneously; extensive damage to buildings; third-degree burns out to about 7 miles; greater than 50% casualties. 2 psi to 1 psi (9 miles to 13 miles): Some persons are injured by flying debris; loss of eyesight; burn and radiation injuries; immediate fatalities less than 25%.
MOTHER EARTH NEWS Staff